Specimen agitator

ABSTRACT

A motor driven agitator providing slow rotational movement of a specimen holder rack with momentary periodic motion in the direction of the rotational axis induces maximum penetration of a treating fluid into specimens held in porous capsules on the rack. A self-aligning, automatic engaging clutch arrangement permits the agitator cover with motor, to be conveniently removed and replaced without complex mechanical components or annoying delays caused by unsuccessful efforts to align separated driving and driven members.

United States Patent 1191 Wilton Aug. 27, 1974 SPECIMEN AGITATOR PrimaryExandner-Morris Kaplan T. B [75] lnvmor Henry Wilton uffalo N YAttorney, Agent, or firm-Alan H. Spencer; W1ll1am Asslgneei American ptal Co po ation, C. Nealon; l-loward R. Berkenstock, 1

Southbridge, Mass. 22 Filed: June 27, 1973 L d f T l l motor nvenagltator provr ing s ow rotationa [21] Appl' 374l82 movement of aspecimen holder rack with momentary periodic motion in the direction ofthe rotational axis [52] U.S. Cl. 118/416, 118/53 i u s max mum pnetration of a treating fluid into [51] Int. Cl. B05c 3/08 specimensheld in p us apsules on the rack. A self- [58] Field of Search 118/416,418, 425, 426, g g, ati ngaging clutch arrangement per- 1 18/417, 52-57;117/ 109, 113 mits the agitator cover with motor, to be convenientlyremoved and replaced without complex mechanical [5 6] References Cit dcomponents or annoying delays caused by unsuccess- UNITED STATES PATENTSful efforts to align separated driving and driven mem- 2,539,s02 1/1951Weiskopf 118/416 hers 2,845,044 7/1958 Cohen 118/425 10 Claim, 9 DrawingFlglll'es PAIENTED mszmn ,55

sum 10$ 2 PATENTEDwszmm saw 20? 2 aia ams a i an IHIIIIIII I SPECIMENAGITATOR BACKGROUND OF THE INVENTION The present invention relates to anagitator, and more particularly to mechanical agitators for efficientlytreating a plurality of specimens with a liquid.

Advanced microscopy'techniques frequently require that specimens beingprepared for examination be subjected to treatment with one or, moreliquids. Such specimens are usually treated with a succession of liquidswith alternate wash or rinse. After treatment, conventional specimenpreparation may include mounting or embedding and slicing to obtain asample ready for examination.

It is of prime importance to obtain maximum contact and circulation ofspecimens with the treating liquid while using a minimum amount ofliquid, i.e.,just sufficient liquid to surround the specimens beingtreated. The specimens being treated are generally placed in some formof porous container to prevent damage to the specimens, preventagglomeration or clumping of specimens and enable identification ofindividual specimens to be maintained by isolation. It is very desirableto use the minimum amount of liquid in treatment, since it is standardpractice to discard the treating liquids without re-use. Efficientcirculation of the treating liquid through porous specimen containersand about the specimens is extremely desirable in order to minimize thetime necessary for treatment. Since treating fluids are frequentlyextremely dilute solutions, efficient circulation is also essential touniformly andthoroughly treat a plurality of specimens.

BRIEF DESCRIPTION OFTHE INVENTION AND DRAWINGS Thorough and continuouscirculation of a treating fluid about a plurality of specimens can beobtained by slowly rotating one or more racks having a plurality ofspecimens in containers about an axis and periodically reciprocating theracks parallel to the axis of rotation. While the speed of rotation isgenerally not critical and is related to the diameter of the specimenholder rack, suitable speeds are usually within the range of 0.1 to 30RPM. It is generally desirable to select a speed which provides aspecimen holder velocity not substantially exceeding feet per minute.While continuous rotation is preferred, it may be desirable to alternatethe direction of rotation periodically. Obviously, rotational motion ina given direction must be continued until at least one completedisplacement has occurred. Periodic axial reciprocation of the specimensduring rotation is conveniently obtained by a cam action by one or moreprotrusions acting on a cooperating member connected to the racks androtating therewith. It is convenient to utilize a tapered orfunnel-shaped base in the agitator assembly having three or more raisedareas spaced equidistant with a conical-shaped member having the samenumber or a multiple thereof, of recessed areas in equidistantcorresponding locations. During rotation of the rack, the conical-shapedmember will periodically engage the raised areas and be axiallydisplaced and periodically return to the lower position as the raisedareas become aligned with the recesses.

It is not essential that the axis of rotation be vertically orientedalthough there are several advantages to such an arrangement. Oneadvantage is that gravity may be used to provide the motivating forcefor the return half of the reciprocal motion and another is that aselfengaging coupling means may be conveniently used to connect thedrive means to the rack drive shaft without proper alignment by theoperator and will fall into engagement during rotation when orientationoccurs.

FIG. 1 is a perspective view of the assembled agitator;

FIG. 2 is a bottom view of the cam member for transferring reciprocatingmotion to the specimens;

FIG. 3 is a front view, partly in section, along plane IIIIII of thecam, showing the cam in its lower most position;

FIG. 4 is a front view in section, along plane IV-IV of the cam, showingmany of the inwardly tapering surfaces of the cam and closure when thecam is in the lower most position;

FIG. 5 is a front sectional view, along plane III-III of the cam,showing the cam in its elevated position;

FIG. 6 is an enlarged, exploded view showing the drive shaft, drivenshaft, and coupling member;

FIG. 7 is a perspective view of the coupling member;

FIG. 8 is an enlarged front view of the drive shaft, driven shaft andcoupling member prior to operative engagement; and

FIG. 9 is an enlarged front view of the drive shaft, driven shaft, andcoupling member in operative engagement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, ahollow body 1, preferably of a clear material such as glass or plastic,which enables the operator to observe the action of the contents, isattached to a mounting plate 2. In the preferred embodiment, the hollowbody defines a cylindrical cavity having a longitudinal axistherethrough. The mounting plate is used to 'mount the agitator assemblyin operative association with apparatus (not shown) to provide desirableliquids for treating specimens with holders 3. A closure 4 is attachedto the mounting plate, more clearly shown in FIG. 3, and has aninwardly-tapering surface of revolution 5 with two pairs ofdiametrically opposed protrusions 6 (only one protrusion shown). It isdesirable to form the closure with an opening near the center of thesurface of revolution to act as an inletoutlet for liquids used inspecimen treatment. Cam 8 has an outwardly tapering surface ofrevolution 9 adapted to meet with inwardly tapering surface ofrevolution 5 as shown in FIG. 4. FIG. 2 illustrates the bottom view ofthe cam showing the outwardly tapering surfaces 9. Recesses in theoutwardly tapering surface 9 are formed by diametrically opposed planarsurfaces 10. Planar recesses are preferred because they provide passagespermitting liquid to pass from one side of the cam to the other. Adriven shaft 11 is connected to cam 8 with its axis aligned coincidentwith the axis of the surface of outwardly tapering surface of revolution9. Driven shaft 11 is adapted to position specimen holder racks 12 andhas axially extending irregular portion 13 adapted to rotate racks l2therewith.

Electric motor 14 is carried by cover 15 which may be secured to thehollow body 1 by screw 16. FIGS. 6, 7, Sand 9 illustrate the preferredmeans for connecting the motor 14 to driven shaft 11. Motor shaft l7hasa pair (only one shown) of diametrically opposed pins 18 near the distalend thereof. Coupling 19 has a generally cylindrical shape with a bore20 in one end thereof, adapted to loosely receive motor shaft 17.Elongated slots 21 are diametrically opposed and attach the coupling tothe motor shaft and permit universal motion of the coupling. Theelongation of slots 21 further permits axial motion of the coupling withrespect to the motor shaft 17. In the other end thereof, an inwardlytapering surface 22 has a cavity 23 with an irregular intersurface 24adapted to rotationally engage driven shaft 11 which is axially moveabletherein. The end 25 of driven shaft 11 is tapered to assist in alignmentand engagement with coupling 19.

In operation, specimens are placed in porous holders 3 which in turn,are supported by racks 12. The racks are conveniently positioned abovecam 8 on shaft 11. It is not necessary that the racks must be fullduring operation, however, it is desirable that the racks haveperforations to assist in providing uniform circulation of the liquid,particularly when the racks are full. In the event that less than a fullrack is desired, it is recommended that specimens be evenly distributedin order to provide most effective circulation of the treating liquid.After the racks have been placed on shaft 11, the subassembly isinserted into the hollow body 1 and rests against closure 4. It is notessential that the cam be in any specific rotational orientation wheninserted in order to obtain proper axial alignment of the driven shaftwithin the hollow body. Because the inwardly tapering surface ofrevolution of the closure meets with the outwardly tapering surfaceofrevolution 9 of the cam and driven shaft is axially aligned therewith,the shaft will be substantially coincident with the axis of the agitatorbody. In the event that the subassembly is placed against the closurewith the outwardly tapering surface of revolution in contact withprotrusions 6, po-

sitioning the protrusions in a diametrically opposed relationshipenables alignment of the driven shaft 11 to be maintained.

The operator next places on body 1, cover 15 which preferably has motorshaft 17 positioned to axially align with the longitudinal axis ofbody 1. It is not necessary for the operator to orient the irregularportion of cavity 23 with the irregular portion of driven shaft 11,since in the event of misalignment, coupling 19 will rest on top of thetapered end of driven shaft 11 as shown in FIG. 8. The tapered surface22 of the coupling, in cooperation with the tapered end 25 of the drivenshaft, assist in axially aligning the coupling to surround the distalportion of driven shaft 11 when properly aligned therewith. After theoperator turns on the motor and the motor shaft begins to rotatecoupling 19, the irregular portion of cavity 23 and the irregularportion 12 of shaft 11 will align during the first complete revolutionof the coupling. Coupling 19 will drop down surrounding the distalportion of driven shaft 11 with the recess 23 as illustrated in FIG. 9upon alignment of the respective portions. Following rotationalengagement of cou pling 19 with driven shaft 11, cam 8 and racks 12 willbe rotated. The rotation of cam 8 causes engagement of alternateportions of outwardly tapering surfaces of revolution 9 with a pair ofdiametrically opposed protrusions 6 as shown in FIG. 5. Engagement ofthe outwardly tapering surfaces of revolution 9 with protrusions 6causes displacement of cam 8 in an axial direction. As rotation of thecam continues and the recesses formed by planar surfaces 10 becomeoriented with protrusions 6, cam 8 moves in an axial direction towardthe inwardly tapering surface 5 of closure 4 until surface 9 is inengagement therewith. This camming action provides periodicreciprocating motion which is transferred to racks 12 during rotation ofthe specimen racks. An added feature of the preferred embodiment isderived from the pumping action which occurs as the cam 8 moves towardand away from inwardly tapering surface 5.

Since it is usually desirable to treat specimens with a plurality ofliquids which are frequently alternated with washes, it is useful tohave an inlet-outlet 7 located at the bottom of the closure 4 throughwhich the liquids may be introduced and withdrawn.

The foregoing description of embodiments of the Applicants invention isgiven by way of illustration and not of limitation. The concept andscope of the invention is limited only by the following claims andequivalents thereof which may occur to others skilled in the art.

What is claimed is:

l. A specimen agitator assembly comprising a hollow open ended body, aclosure for one end of said body, said body and closure being adapted tocontain a liquid for treating a specimen, said closure having aninternal inwardly-tapering surface of revolution, at least threeequidistant raised areas on said inwardly-tapering surface, a rotary camhaving a tapering surface of revolution adapted to cooperate with saidinwardly-tapering surface, said cam having at least three equidistantrecesses on said tapering surface on said cam to receive each of saidraised areas, means to support at least one specimen within said body,said means being connected to said cam, and drive means to rotate saidcam and said specimen thereby provides periodic reciprocal axialdisplacement of said specimen through the combined action of the raisedareas and cam to provide circulation of the treating liquid.

2. The specimen agitator according to claim 1 wherein there are fourraised areas on said inwardly surface and four recesses on said taperingsurface on the cam.

3. The specimen agitator according to claim 2 wherein the raised areashave a hemispherical surface and the tapering surface of said cam hasfour regularly spaced planar surfaces providing said recesses.

4. The specimen agitator of claim 1 wherein said drive means includes anelectric motor having a driving shaft, a coupling axially connectedthereto, and a driven shaft, said coupling surrounding at least aportion of said driven shaft.

5. The secimen agitator of claim 4 wherein said coupling comprises agenerally cylindrical member slidably and universally connected at oneend to the distal end of said driving shaft, said cylindrical memberhaving a recess in the opposite end thereof to slidably engage andsurround a portion of said driven shaft.

6. The specimen agitator of claim 5 wherein said recess in the oppositeend of the cylindrical member has an inwardly-tapering surface ofrevolution to assist alignment of said driven shaft.

7. The specimen agitator of claim 2 wherein said body has a generallycylindrical chamber therein and is positioned with the axis thereofgenerally vertical and said drive means includes a motor having a driveshaft, a releasable coupling attached to the distal end thereof and adriven shaft having at least a portion of one end adapted to besurrounded by said coupling, the other end of said driven shaft beingconnected to said cam and said driven shaft being substantially axiallyaligned with the axis of said cam whereby said conical member is rotatedabout the axis thereof and reciprocates in a direction parallel to theaxis thereof in response to alternate engagement of said raised areas onsaid tapering surface of the cam.

8. The specimen agitator of claim 7 wherein said releasable coupling isa generally cylindrical member slidably and universally connected tosaid driving shaft at one end; the other end of said cylindrical memberhaving a recess of generally increasing depth in a direction toward theaxis thereof and an axially aligned cavity at the apex of said recessadapted to releasably engage said one end of said driven shaft totransfer rotational motion from said driving shaft to said driven shaftand to permit axial reciprocation of said driven shaft withoutdisengagement.

9. The specimen agitator of claim 8 wherein the drive shaft has a pairof diametrically opposed pins extending radially outward from saiddriving shaft, said cylindrical member has a pair of diametricallyopposed slots extended in an axial direction and to receive said pins,said cylindrical member having a bore in said one end, said bore beinglarger than said driving shaft to provide limited freedom of movement ofsaid cylindrical memher, a cover to close the other end of said bodywith said motor being positioned to align said driving shaft insubstantially axial alignment with said body and driven shaft, wherebysaid closure generally aligns said driven shaft and cam with the drivingshaft, and gravitation forces act on said releasable coupling to engageit with said driven shaft during the first revolution of said drivingshaft.

10. The specimen agitator of claim 8 wherein said closure has a passagetherethrough at the apex of the surface of revolution to introduce andwithdraw liquids for treating the specimen.

1. A specimen agitator assembly comprising a hollow open ended body, aclosure for one end of said body, said body and closure being adapted tocontain a liquid for treating a specimen, said closure having aninternal inwardly-tapering surface of revolution, at least threeequidistant raised areas on said inwardly-tapering surface, a rotary camhaving a tapering surface of revolution adapted to cooperate with saidinwardly-tapering surface, said cam having at least three equidistantrecesses on said tapering surface on said cam to receive each of saidraised areas, means to support at least one specimen within said body,said means being connected to said cam, and drive means to rotate saidcam and said specimen thereby provides periodic reciprocal axialdisplacement of said specimen through the combined action of the raisedareas and cam to provide circulation of the treating liquid.
 2. Thespecimen agitator according to claim 1 wherein there are four raisedareas on said inwardly surface and four recesses on said taperingsurface on the cam.
 3. The specimen agitator according to claim 2wherein the raised areas have a hemispherical surface and the taperingsurface of said cam has four regularly spaced planar surfaces providingsaid recesses.
 4. The specimen agitator of claim 1 wherein said drivemeans includes an electric motor having a driving shaft, a couplingaxially connected thereto, and a driven shaft, said coupling surroundingat least a portion of said driven shaft.
 5. The secimen agitator ofclaim 4 wherein said coupling comprises a generally cylindrical memberslidably and universally connected at one end to the distal end of saiddriving shaft, said cylindrical member having a recess in the oppositeend thereof to slidably engage and surround a portion of said drivenshaft.
 6. The specimen agitator of claim 5 wherein said recess in theopposite end of the cylindrical member has an inwardly-tapering surfaceof revolution to assist alignment of said driven shaft.
 7. The specimenagitator of claim 2 wherein said body has a generally cylindricalchamber therein and is positioned with the axis thereof generallyvertical and said drive means includes a motor having a drive shaft, areleasable coupling attached to the distal end thereof and a drivenshaft having at least a portion of one end adapted to be surrounded bysaid coupling, the other end of said driven shaft being connected tosaid cam and said driven shaft being substantially axially aligned withthe axis of said cam whereby said conical member is rotated about theaxis thereof and reciprocates in a direction parallel to the axisthereof in response to alternate engagement of said raised areas on saidtapering surface of the cam.
 8. The specimen agitator of claim 7 whereinsaid releasable coupling is a generally cylindrical member slidably anduniversally connected to said driving shaft at one end; the other end ofsaid cylindrical member having a recess of generally increasing depth ina direction toward the axis thereof and an axially aligned cavity at theapex of said recess adapted to releasably engage said one end of saiddriven shaft to transfer rotational motion from said driving shaft tosaid driven shaft and to permit axial reciprocation of said driven shaftwithout disengagement.
 9. The specimen agitator of claim 8 wherein thedrive shaft has a pair of diametrically opposed pins extending radiallyoutward from said driving shaft, said cylindrical member has a pair ofdiametrically opposed slots extended in an axial direction and toreceive said pins, said cylindrical member having a bore in said oneend, said bore being larger than said driving shaft to provide limitedfreedom of movement of said cylindrical member, a cover to close theother end of said body with saiD motor being positioned to align saiddriving shaft in substantially axial alignment with said body and drivenshaft, whereby said closure generally aligns said driven shaft and camwith the driving shaft, and gravitation forces act on said releasablecoupling to engage it with said driven shaft during the first revolutionof said driving shaft.
 10. The specimen agitator of claim 8 wherein saidclosure has a passage therethrough at the apex of the surface ofrevolution to introduce and withdraw liquids for treating the specimen.